These cork balls are made by Rawlogy.  Below is their description.  Rawlogy Ultralight Travel Pouches are also available here.

Made from 100% sustainable cork, Rawlogy's firm cork massage ball relieves muscle pain and provides tension relief. Plus, it's completely free of chemicals like BPA, plastics, PVC and petroleum. This ball is light, compact, convenient, eco-friendly, and travel-ready! It's perfect for rolling out sore and achy muscles, stimulating fitness recovery, reducing stiffness, and improving mobility.

Sizes:

Mini: 1.9 in (4.83 cm), 0.7 oz (20 g).

Classic: 2.5 in (6.35 cm), 1.4 oz (40 g).